1. Field of the Invention
The present invention relates to an apparatus, system, and method for remotely verifying the integrity of a device for a mobile platform. When both the device and the verification apparatus, which is connected to the device via a network, share private information, the apparatus and system can remotely check the integrity of the device by authenticating the device by comparing a check code generated by a verification apparatus with a check code generated by the device and determining whether the two check codes match each other.
2. Description of the Related Art
FIG. 1 illustrates a conventional method for verifying the integrity of a device.
Referring to FIG. 1, television set-top boxes, mobile telephones, local area network (LAN)-based or wide area network (WAN)-based personal computers (PCs) and remote network equipment, such as small-sized sensors, are susceptible to attacks from hackers since network hosts or service providers have limited capabilities in controlling user access to devices. Furthermore, it is difficult for network hosts or service providers to check remote devices physically and determine whether the remote devices have been changed, for example, whether unauthorized users have accessed software applications on a network. Therefore, there is a need for a technique to verify the integrity of a memory in a remote device in a network environment. Here, integrity refers to the certainty that only authorized people are allowed to access or change the information on data and the certainty of network security.
Conventional methods of verifying the integrity of a memory in a device include comparing a digest value for selected software with a hash value for a memory area in a remote device.
The conventional method of verifying the integrity using a hash value for a memory area in a device is disclosed in U.S. Patent Publication No. 2002/0138544. In this method, a random seed is inserted into a memory area to obtain a hash value. And then the random seed, a hash function and the information about the memory area to be tested are sent to the device. The device produces the hash value of the memory area using the information received from a verification apparatus and sends the generated hash value to the verification apparatus. The verification apparatus compares its generated hash value for the memory area with the hash value generated by the device and checks the integrity of the memory area based on a comparison result.
This method uses the hash value for a memory area to verify the integrity. For this reason, if a malicious code such as virus changes its position and attacks different parts of the memory, the integrity check will be successful when it should not be successful. As a result, the verification apparatus cannot correctly verify the integrity of the device.
The conventional method of verifying the integrity of a device using a digest value of selected software is disclosed in U.S. Pat. No. 6,748,538. In this method, the digest value for the software installed in the device is stored with a signature in a memory. The integrity of the software is checked by comparing the signed digest value with the digest value obtained by applying a separate hash function to the selected software. However, this method has a limitation in that it can verify only the integrity of the software stored in the device.
U.S. Pat. No. 6,138,236 discloses a method of verifying the integrity of software with a code stored in a programmable read only memory (PROM) which checks the signature of the software during booting. However, this method can internally check the integrity of software only during booting. A separate secure mechanism is needed to externally check the integrity of software since it is impossible to correctly check the integrity when an attacker changes the contents of a PROM and creates a valid check code.
Accordingly, there is a need for an integrity verification method capable of coping with a malicious code that attacks different parts of a memory and externally verifying the integrity of a device during runtime as well as during booting of the device.